The invention relates to an arrangement for the projection of cantilever sections of multi-section bridge supporting structures of steel or prestressed concrete forming a superstructure, and particularly to such an arrangement having two concreting scaffolds each composed of a supporting part with crossbeams arranged above the superstructure of the bridge and provided with traveling gears or rollers. A platform is suspended from the supporting part and arranged below the superstructure carrying casings for extending the superstructure sections. A traveling auxiliary beam spans at least one of the superstructure sections and is arranged above the superstructure being supported on retractable supporting blocks.
In the production of superstructures for bridges using sectional cantilever projections, so-called "projection cars" which are carried on the section of the existing superstructure and project beyond this bridge or superstructure section, are known. The projection cars carry a casing, for the next section to be connected, on a platform arranged underneath the superstructure (see German Pat. No. 973,407). These projection cars are particularly suitable for the production of double cantilevers projecting from a support which can then be assembled to the bridge supporting structure by joining the cantilever ends.
A disadvantage of these projection cars is that of the two projection cars required for the production of a double cantilever, one must always work in the direction in which the bridge sections are being extended, while the other works in the opposite direction. The special design of these projection cars, having a platform arranged underneath the superstructure, which carries the casing, has the effect that the space below the bridge is blocked by this platform so that these cars can not pass by the bridge piles of multi-section bridges. In order to transport the projection cars after the completion of one of the superstructure sections, they must be disassembled, transported on land to the next support or pile and be assembled there again.
Furthermore, since the projection cars are carried on the finished bridge section and project for the construction of the next section, they are only supported by a pile when the section of the superstructure directly above the pile is already concreted in the respective direction of projection. But these operations require a separate casing which must be either arranged on the pile or which rests on the terrain.
In a known arrangement of the above described type it is known to use traveling concreting scaffolds which are suspended on a scaffold carrier arranged above the superstructure, (see German Pat. No. 1,225,695). In these concreting scaffolds, which have a platform suspended over hangers, arranged underneath the superstructure of the bridge and carry the casing, the loads are transposed from the concreting scaffold, and the respective bridge section to be built, to the bridge pile. The scaffold carrier must therefore be very heavy. This disadvantage can not be completely eliminated even if the auxiliarly beam, as it is also sometimes referred to, bears progressively next to the section to be produced on the finished superstructure section (see German Pat. No. 1,263,806).
It is an object of the invention to overcome the foregoing problems and to be able to use concreting scaffolds which can travel on the superstructure and project above a completed cantilever end, and to be able to transfer these concreting scaffolds with an auxiliary beam arranged above the superstructure to the next pile.